Regenerative heat exchangers



Jan. 8, 1963 P. w. s. PERSSON 3, 7

REGENERATIVE HEAT EXCHANGERS Filed March 29, 1955 4 Sheets-Sheet 1 w Wm; W

w 24, 24 w. 422 Z /4 I U. y; I /Z4 2 912 7 0 /06 m4 5/ 1g m i6 -55 w w 72 f Jan. 8, 1963 P. w. s. PERSSON 3,072,132

REGENERATIVE HEAT ,EXCHANG ERS Filed March 29. 1955 4 Sheets-Sheet 2 INVENTOR.

Jan. 8, 1963 P. w. s. PERSSON REGENERATIVE HEAT EXCHANGERS 4 Sheets-finest 4 Filed larch 29, 1955 flu EINVENTZR.

United rates Fat-em: @hdce 3,'Z2,l32 Patented Jan. 8, 1963 3,072,132 REGENERATEVE HEAT EXCHANGERS Per Walther Sigvard Persson, lohanneshov, Sweden, as-

signor to Svensha Rotor Masldner Alrtieholag, Naclra, Sweden, a corporation of Sweden Filed Mar. 29, 1955, Ser. No. 497,619 12 Claims. (Cl. 165-9) The present invention relates to improvements in and relating to regenerative heat exchangers of the rotary type and particularly to the adaptation thereof to a new kind of rotor, the rotor comprising an annulus having inner and outer shell walls defining the same and bearing means for rotatably supporting the rotor at the inner shell wall thereof with respect to the stationary casing component of the apparatus.

According to a conventional design the rotor includes a central shaft suspended by a support bearing mounted above the rotor and steadied at its lower end by a guide bearing. The rotor is divided into sector shaped compartments by means of radially extending partition walls and the sector shaped compartments are filled by heat transferring plates, said plates upon rotation of the rotor first accumulating heat from the hot gases and then, after entering the air side, delivering the accumulated heat to the air. The shaft needs only to be dimensioned to meet the requirements as to structural strength and for that reason the inner ends of the sector shaped compartments become too narrow in width and not worthwhile to be filled with heat transferring plates. Therefore, it is customary to cut off the inner end of the sector shaped compartments by means of transverse wall sections and to cover these inner sector subcompartments by means of annular disc closures attached to either end of the rotor.

It is obvious that in the conventional design of the devices to which the invention relates a centre portion of the rotor exists which is of little use for heat exchange purposes. Therefore, it is a first object of the invention to derive advantages from the inactive centre portion of the rotor to the end that this space may provide for an attachment for revolving the annular rotor equipment which will provide the equipment with a ball bearing assembly on which the rotor is carried by its own weight on which the same can be operated and wherein one of the races is attached to the rotor as a carrier for the same while the other race serves as a support for connecting the assembly to a structural framework supporting the heat exchanger and wherein access can be readily had to the interior of the race members for removal or changing of the ball bearings.

Other objects of the present invention are to provide a ball bearing assembly as the single means on which the rotor weight is carried at the inner periphery of the annular rotor equipment whereby the distortions of the rotor due to heat expansion during the operation of the apparatus are of minimum value so that the rotor weight is distributed to as many balls as possible around the ball bearing assembly. A further object is to provide a bearing assembly for the rotor having sufficient width to carry the rotor without any risk involved of tilting of the rotor and in which any guide bearing means otherwise customary can be dispensed with. Still other objects are to provide a ball bearing assembly upon which the rotor is self centering and in which coaxial relationship between the races and the rotor and full registering between both the races is maintained.

Another object is to provide an attachment for revolving the rotor equipment which is inexpensive to manufacture, the bearing races of which are readily turned in a common lathe, and which attachment is easy to install and remove and eflicient in operation. As the bearing assembly is arranged at the inner periphery of the rotor equipment the weight of the bearing means will be far less than in an arrangement of the bearing assembly in which the same is located at the outer periphery of the rotor. Less expensive and improved means for peripheral drive of the rotor can be attached to the rotatable member of the bearing assembly.

A further object is to provide a structural framework supporting said exchanger and including a hub portion encircled by the rotor and carrying the lower supporting member of the bearing assembly. The casing enclosing the rotor does not carry the rotor as in common heat exchanger designs heretofore and because of this feature the shell thereof can be made thin walled and comparatively light.

It is therefore an additional object of the present invention to provide a new and improved preheater construction which for a given size and capacity is materially lighter and less expensive than the presently best available constructions, and which provides further advantages the nature and details of which will appear more fully as this specification proceeds.

Other features and advantages of the present invention and the manner in which it may be carried into practice will become apparent upon consideration of the following detailed description of different examples of constructions embodying the principles of the invention and illustrative by way of example but without limitation. Reference is bad to the accompanying drawings in which:

FIG. 1 is a vertical central section, taken on line 1-1 of FIG. 2, of a rotary regenerative heat exchanger supported from below and embodying the principles of the invention.

FIG. 2 is a partial top plan view taken. on line 2-2 of p the heat exchanger shown in FIG. 1.

FIG. 3 is an elevation, partially broken, of another similar form of heat exchanger according to the invention.

FIG. 4 is an elevation, partially broken, of a further similar form of heat exchanger according to the invention.

FIG. 5 is an elevation, partially broken, of another similar form of heat exchanger according to the invention.

FIG. 6 is an elevation; partially broken, of still another similar form of heat exchanger according to the invention.

FIG. 7 is a partial bottom plan view of the heat exchangers shown in FIGS. 1 to 6.

FIG. 8 is a vertical section of a heat exchanger according to the invention but suspended from above.

FIG. 8a is a sectional view of a modified detail of an arrangement in FIG. 8.

FIG. 9 is a fragmentary broken vertical section on enlarged scale of the bearing means such as shown in FIG. 1.

Referring now more particularly to FIGS. 1, 2, 7 and 9, there is illustrated one suitable form of preheater for carrying the invention into effect. The apparatus shown comprises a stationary outer casing structure, indicated generally at it having a shell 12, which advantageously is of relatively thin section because of weight considerations, and spaced end plates 14 and Ira between which the rotor is mounted. End plate 14 is provided with two sector shaped openings or ports 13 and 2t) located generally on opposite sides of a diametral plane through the heat exchanger. These ports are connected respectively with ducts 22 and 24 for conducting one of the heat exchanging fluids to the rotor and the other fluid from the rotor. End plate 16 is likewise provided with sector shaped ports 26 and 28, aligned respectively with ports 18 and 29 in end plate 14 and communicating respectively with ducts 3d and 32 for conducting the first mentioned fluid from the rotor and said other fluid to the rotor. Countercurrent flow of the two fluids provides for most efficient heat transfer and in accordance with that practice the apparatus illustrated is advantageously connected so that for example cold air to be heated is admitted through duct 3%) and port 26 to the bottom of the rotor and after being heated is discharged therefrom through port and duct 22, as indicated by arrow 34;, while hot gas to be cooled enters through duct 24 and port 2%) to flow downwardly through the rotor and be discharged in the direction of arrow 36 through port 2? and duct "'2. With such connections it will be evident that the upper end of the apparatus will be hotter than the lower end when in use and for convenience the end of the apparatus to which fluid to be cooled is admitted and from which heated fluid is discharged will be referred to as the hot end, the opposite end being referred to as the cold "it will be obvious that either the upper end or the lower end may be the hot one, so long as countercurrent flow is maintained depending upon which ducts are connected to the sources of supply of the diiierent fiuids.

To the lower end plate 16 of the casing a structural framework is attached comprising two L-beams 3S and 40 running across the end plate 16 and defin'ng simultaneously the inner side walls of the ducts 3d and 32 and further two edgewise raised plates 42 and arranged symmetrically on opposite sides of a diametral plane at right angles to the diametral plane on opposite sides of which the ducts E36 and 32 are located. The rounded portions 46 and 43 of the central part St? between the ports 26 and 28 of the end plate 16 are connected to the lower inner ends of the ducts 30 and 32, respectivel by means of appropriately curved plates 52 and 54.

To the upper surface of end plate 16 an inner cylindrical shell 56 is secured which is closed at its upper end by a disc 53 and serves as a hub for supporting the rotor by means of a bearing indicated generally at as the nature of which will later be described more in detail.

In order to strengthen the upper end plate 14 to the same, two plate beam members 62 and 64 are secured generally in alignment with the beams 38 and and at the centre thereof having circularly outwardly bent portions 66 and 63 registering with the circumference of the hub 56.

The rotor encircling the hub portion 56 and indicated generally at 70 comprises an annulus having inner and outer shell Walls 72, and 74 and radial partition walls 76 dividing the space between the shell walls into sector shaped compartments 78 which are provided at or near their bottoms with suitable supports as bars 84) supporting regenerative heat exchanging plate elements 82 in accordance with Well known practice.

In accordance with a basic feature of the present .invention the rotor '76 is rotatably supported at its inner periphery by the hearing so, rather than at or adjacent the 5'.

centre or axis of rotation, the many advantages of peripheral support hereinafter to be pointed out being secured by the provision of bearing construction the nature and functioning of which enables the practical and economical application of peripheral support to be obtained inexpensively and with not only a long life factor but also relative ease or repair and replacement when wear does occur.

The lower bearing member comprises a rigid ring which is provided with a load-carrying raceway 3a in the form of an annular recess which may be cut directly in said bearing member itself and in the corners or" which are located arcuate lengths of wire 8?; providing lower rails upon which a multiplicity of ball 96 may roll.

The upper rotatable bearing member 92 comprises a rigid ring having an annular recess forming the upper raceway for the balls 9% and registering with the lower raceway 86. Additional arcuate lengths of wire 88 in the corner of recess 94 provide upper rails engaged in rolling contact by balls 98, the latter being held in evenly spaced relation peripherally by a retainer 96.

The joints in the lower rails and in the upper rails should be staggered both with respect to each other but also the joints in the upper rails with respect to the joints in the lower rails, so that no ball passes over more than one joint at a time.

The rotatable bearing member 52 is provided with a circumferential downwardly directed annular extension 98 which at its lower end passes over into an outwardly directed flange lltl. Said annular extension 98 forms a diaphragm portion of sufficiently thin section in radial direction to flex enough to compensate for rotor distortion without imposing undesirably high stresses on the ring 92. At its inner periphery the rotor 7% is provided top thereof with a corr spending inwardly directed 132 secured to the ltiil so that rotor is suspended from the rotatable b-earin= member @2. To the upper end of the rotatable bearing member a disc tea is secured which is provided with an upwardly directed shaft tea on which a gear wheel N8 is mounted with wh ch the driving gear 11% for turning the rotor 76 meshes. The driving motor 112 is mounted on a vertical plate 314 secured to the two beams 52 and on he top of the casing and further supported by spaced standards lie adapted to rest on a horizontal supporting plate lit; secured to the beams s2 and 64. To shield the bearing Gil and the gearing 168, Kid from heat radiation from the adjacent ducts 22 and 24, respectively, conducting the heated air discharged from the preheater and the hot gas admitted to the same and to seal them ofi from entrance to the same of said hot media the bearing and the gearing are surrounded by appropriate jacket enclosures 12d and 122, respectively, of which the latter may be adapted to carry a lubricant for the gearing While the bearing due to its construction can be left ungreased. Further, in order to minimize the heat radiation therefrom the ducts 22. and 2 at the hot end of the preheater as well as the inner and outer shells 72 and 74 of the rotor are provided with heat insulation coverings 124, 126 and 128, 13%, respectively.

For cooling of the bearing and protection of the same from soot deposits from the fluid passages of the preheater a continuous flow of barrier gaseous medium such as cool pressure air can be forced from the inside of the bearing, said stream of air for instance entering the hub portion 56 through an aperture 132 in the central part 5%) of the end plate 16 from a supply of air under pressure and being admitted through an aperture 134 in the middle of the disc 58 of the hub into the interior of the bearing 66 and departing therefrom through the interspace between the lower and upper bearing members 84 and 92, respectively, into the clearance 136 between the hub 56 and the inner rotor shell 72 from which it is discharged into the passages for the heat exchanging fluids.

It will be noted that the mounting and demounting of the preheater is extremely simplified as all the parts thereof are built up on a basic supporting plate. At demounting of the preheater for inspection and repair the upper end plate and the shell of the casing are easily removed while the rotor can remain standing. The bearing and the driving gears are light and cheap and can be turned in a common lathe and further are readily accessible and inexpensive to exchange and replace.

The preheater according to FIG. 3 differs from the construction just described mainly in that to the upper end plate 14 of the casing is secured a ring member 138 having two downward directed annular cam flanges 14s and 142, the inner of which 140 extends into a groove 144 provided in the flange tilt? of the upper bearing member $2 and the outer of which 142 extends into the interspace 146 between the rim of said flange lilo and an adjacent annular sealing strip 148 provided on the inner periphery of the rotor. By means of these ridge and groove portions the positions of which may be the reverse a labyrinth seal is provided for between the inner top end of the rotor and the upper end plate of the casing. The gear wheel 150 attached to the upper bearing member 92 may be shrunk on the latter. The barrier cooling air for the bearing is supplied from above through an opening 152 in the top of an enclosing jacket 15d surrounding the gearing as well as the bearing while the hub 56 is closed at its top 58.

The general arrangement of the preheater shown in FIG. 4 is chiefly in accordance with the construction according to FIGS. 1 and 2. To a shaft 106 provided on a disc 104 secured to the upper bearing member is fastened a pulley 156 which is belt or chain driven from the driving pulley 158. The belt or chain driven pulleys are not shielded off from the ambient atmosphere but the bearing is surrounded by a jacket enclosure 16th and no provisions for flow of barrier or cooling air therethrough are made.

In the construction shown in FIG. 5 the bearing means 162 are located adjacent the lower end of the rotor 164, the upper end of the apparatus being the hot end of the preheater, for example, and the lower end being the cold end of the preheater as shown by means of the arrows 166 and 168, respectively, indicating the direction of flow of the admitted hot medium and the direction of flow of the discharged heated medium, respectively. To the lower end of the inner shell 72 of the rotor a disc 170 is secured forming the upper bearing member of the bearing 162 and being provided with a downward directed extension 172 on which a gear wheel 174 is shrunk which meshes with the driving gear 110. The lower end plate 16 of the casing has a central opening 176 to the inner edge of which an annular hub 178 is secured which serves as carrier for the lower bearing member 180 of the bearing, and the upper bearing member 179 and the hub are provided with cooperating cam flanges and grooves to provide for a labyrinth seal 182. Protection air is entered through duct 184 in the cover 186 which closes the bottom of the space containing the gearing and the bearing means.

The embodiment according to FIG. 6 diflers from that of FIG. 5 mainly in that the bearing means 138 are located adjacent the middle portion of the rotor instead of at or adjacent th lower end of the rotor. To the inner shell 72 of the rotor a ring 1% is attached to the lower surface of which an annular member 192. is secured forming the upper bearing member. Between the confronting surfaces of the ring 196 and the upper bearing member 192 a heat insulation 1% may be inserted. Further, to the underside of the ring 1% a carrier 196 for the driven gear wheel 174 is secured which carrier 196 is closed at its top and attached thereby to the ring 1% and has an axially extending cylindrical wall portion to the end of which the gear wheel 174 is shrunk upon. The lower bearing member 198 is carried by a cylindrical support 2% the lower end of which is fastened to end plate 16 of the casing. The lower bearing member has radially spaced inner and outer annular cam flanges 2132 and 264 engaging grooves 296 and 268 which are arranged in the upper bearing member 192.

In the construction hitherto contemplated the structural framework has been placed below the heat exchanger, the casing, which as well as the hub carrying the rotor, have been mounted on the structural framework.

However, it is also possible to let the casing and the rotor carrying hub be suspended from a structural framework and such an arrangement is illustrated in FIG. 8. The structural plate framework comprises two horizontal T-beams 21%) and 212 similar to the beams 62 and 64 in FIG. 2 and the central portions of which are bent in a proper way to surround the hub arrangement 214 for the rotor. The upper end plate 14 of the casing has a central aperture 216 for the entrance of the hub 214 carrying the rotor, said hub comprising upper and lower portions 213 and 220, respectively, fastened together detachably and of which the upper hub portion is fastened to the upper bent ends of the beams 210 and 212. The lower half of the hub has a radially extending flange 222 at its lower end which is provided with a raceway 224 on its upper face and a coaxial raceway 226 on its lower face. To the top rim of the inner shell 72 of the rotor a ring flange 228 is secured which has a raceway 230 provided on the upper surface of the same registering with the lower raceway 226 on the flange 222. To the ring flange 228 of the shell 72 of the rotor is further fastened an extra bearing ring member 232 extending upward and having an inward flange 234 which on its lower surface has a raceway 236 registering with the upper raceway 224 of the flange 222. By means of the two superimposed bearings a bearing is obtained which is very safe from misalignment, derailing or tilting due to stresses in radial as Well as axial directions, even if the rotor is built extremely light. In order to show a further alternative the peripheral drive is effected by a pin rack 238 located at the outer periphery of the rotor on the outer shell 74 of the rotor meshing with a driving gear (not shown). The open ends of the inner shell of the rotor are covered by plates 24-4 and 24-2.

FIG. 8a shows a tandem bearing similar to that of FIG. 8 but in which the bearing member attached to the hub is that on which has the two axially most spaced raceways instead of the bearing member attached to the rotor. FIG. 8a is believed to be self explanatory and not in need of further description.

The centre space of the rotor which as stated above is not economically worhwhile to utilize in practice for heat exchange purposes and which has been referred to hereinbefore as an inactive portion of the rotor varies in extent but has advantageously a radius within the limits 10 to 25 inches due to the size of the preheater and preferably the radius of the inner shell of the rotor lies within 12 to 20 inches.

From the foregoing it will be obvious that the principles of the invention may be carried into eflect by means of a Wide variety of specific structural embodiments, that various features may be combined in different Ways and that certain features may be employed to the exclusion of others. The invention is accordingly to be understood as embracing all forms of apparatus falling within the scope of the appended claims.

What I claim is:

l. Regenerative heat exchanger of the vertical type for gaseous media comprising a casing providing passages therethrough for hot and cold gases, respectively, aligned inlet and outlet ducts connected to the ends of said passages to provide for flow of the hot and cold gases through said exchanger, a stationary structural framework supporting said exchanger and including a vertically disposed hub portion, a rotor with inner and outer shells having the interspace therebetween filied with regenerative heat exchange material, said rotor being enclosed within said casing and encircling said hub portion, and bearing means for rotatably supporting the rotor solely at the inner periphery thereof with respect to said hub portion, said bearing means comprising two bearing members co-axial with the rotor, one of said bearing members being attached to said hub portion and stationary with respect thereto, and a second one of said hearing members being attached to the rotor and mounted to rotate therewith.

2. Regenerative heat exchanger as claimed in claim 1,

in which the bearing means comprises a lower supportrecess in the lower supporting member, arcuate lengths 4. Regenerative heat exchanger as claimed in claim 3, in which an inner shell of the rotor is provided with an inward extending flange and the rotatable bearing meirn her with an outward extending flange, by means of which flanges the rotor and the rotatable bearing member ar connected with each other.

5. Regenerative heat exchanger as claimed in claim 4, in which the rotatable bearing member transists over into its outward extending flange by means of a flexible diaphragm portion coaxial with the rotor axis.

6. Regenerative heat exchanger as claimed in claim i, in which means are provided for peripheral drive of the rotatable bearing member and thereby of the rotor.

7. Regenerative heat exchanger as claimed in claim 6, in which a peripheral toothed rack is attached to the retatable bearing member and a driving gear meshing with said peripheral toothed rack and carried by the casing is provided for turning the rotatable bearing member and thereby of the rotor.

8. Regenerative heat exchanger as claimed in claim 1, in which the rotatable bearing member confronts an end plate of the casing, one of which rotatable bearing member and casing end plate is provided with at least one annular ridge coaxial with the rotor axis and the other of which is provided with a corresponding annular groove to receive said annular ridge in order to provide for a labyrinth seal.

9. Regenerative heat exchanger as claimed in claim 1, in which the hub portion is supported by the structural framework and terminates below the middle portion of the rotor and carries the stationary bearing, member, and the rotatable bearing member is attached to the inner shell of the rotor as a disc across the rotor ax said disc being provided with a downward directed annular extension which at its lower end is provided with a peripheral toothed rack to mesh with a driving gear for turning the rotor.

10. Regenerative heat exchanger as claimed in claim 9, in which at least one of the hub portion and the annular extension includes a flexible diaphragm portion c0- axial with the rotor axis.

generative heat exchanger as claimed in claim 1, the hub portion and the casing are suspended an upper structural framework and the hub portion carries the stationary bearing member, and the T0- tatable bearing member attached to the rotor is carried by the stationary bearing member.

12. Regenerative heat exchanger as claimed in claim 1, in which one of the two bearing members comprises two detachable sections each provided with an annular recess coaxial with the rotor and said recesses facing each other in axially spaced relation, and the second of the two bearing members having an upper and a lower recess on opposite sides thereof, the upper recess of the second bearing member registering with the upper recess of the first bearing member and the lower recess of the second bearing member registering with the lower recess of the first hearing m mber, arcuate lengths of Wire located in the corners of said recesses, and anti-friction bearing elements engaged in rolling contact with the lower and upper rails by said arcuate lengths of wire located in said annular recesses.

rteierenees (li ter? in the file of this patent UNITED SrATES PATENTS 2,744,731 Brandt May 8, 1956 2,803,508 Nilsson et a1. Aug. 20, 1957 FOREEGN PATENTS 649,265 Great Britain Jan. 24, 1951 1,082,683 France Dec. 31, 1954 

1. REGENERATIVE HEAT EXCHANGER OF THE VERTICAL TYPE FOR GASEOUS MEDIA COMPRISING A CASING PROVIDING PASSAGES THERETHROUGH FOR HOT AND COLD GASES, RESPECTIVELY, ALIGNED INLET AND OUTLET DUCTS CONNECTED TO THE ENDS OF SAID PASSAGES TO PROVIDE FOR FLOW OF THE HOT AND COLD GASES THROUGH SAID EXCHANGER, A STATIONARY STRUCTURAL FRAMEWORK SUPPORTING SAID EXCHANGER AND INCLUDING A VERTICALLY DISPOSED HUB PORTION, A ROTOR WITH INNER AND OUTER SHELLS HAVING THE INTERSPACE THEREBETWEEN FILLED WITH REGENERATIVE HEAT EXCHANGE MATERIAL, SAID ROTOR BEING ENCLOSED WITHIN SAID CASING AND ENCIRCLING SAID HUB PORTION, AND BEARING MEANS FOR ROTATABLY SUPPORTING THE ROTOR SOLELY AT THE INNER PERIPHERY THEREOF WITH RESPECT TO SAID HUB PORTION, SAID BEARING MEANS COMPRISING TWO BEARING MEMBERS CO-AXIAL WITH THE ROTOR, ONE OF SAID BEARING MEMBERS BEING ATTACHED TO SAID HUB PORTION AND STATIONARY WITH RESPECT THERETO, AND A SECOND ONE OF SAID BEARING MEMBERS BEING ATTACHED TO THE ROTOR AND MOUNTED TO ROTATE THEREWITH. 